As the network technology is improved, a network service which provides various services to users via a network has come to draw attention. A service provider who provides services prepares, for example, a platform for executing a software package or application software in a data center.
In a data center, a plurality of racks is installed in a room and a plurality of servers is accommodated in each rack. Jobs are organically distributed to each server according to the operation states of the servers and as a result, a large number of jobs are efficiently processed.
In the meantime, servers generate a large amount of heat as they operate. Since the increase of the temperature of the servers may cause deterioration in performance or a malfunction, or becomes the cause of a failure, cold air is taken into the rack using a cooling fan and the heat generated within the rack is discharged to the outside of the rack.
In the meantime, a large amount of electric power is consumed in the data center, and thus, reduction of power consumption is required from the view point of saving energy. A general data center is configured such that the outside air is not allowed to infiltrate into the room in which the rack is installed and the temperature of the air supplied into the rack is adjusted using an air conditioner.
With respect to the data center, an electric power saving data center has been developed in which the servers are cooled down by using the outside air. Especially, in a data center directly cooled down by the outside air by directly introducing the outside air into the room, the electric power consumed in cooling down the servers may be substantially reduced compared to a general data center having no such features.
The following are reference documents:    [Document 1] Japanese Laid-Open Patent Publication No. 61-225897 and    [Document 2] Japanese Laid-Open Patent Publication No. 2013-104639.